Catalyzed sulfide-hydrocarbon reaction products and method of making same



Patented Jan. 1, 1952 UNITED STATES PATENT OFFICE CATALYZED MAKING SAMESULFIDE-HYDROCARBON RE- ACTION PRODUCTS AND METHOD OF poration of OhioNo Drawing. Application August 24, 1946, Serial No. 692,930

19 Claims.

The present invention relates to improvements in lubricants andhasspecific reference to the treatment of hydrocarbons with a phosphorussulfide to form lubricants and lubricant additives having improvedproperties, especially with reference to the inhibition of oxidation andmanifestations resulting therefrom.

Hydrocarbon-phosphorus sulfide reaction products have desirablelubricant properties and are frequently incorporated in lubricating oilsto improve the strength of the lubricating film, impart anti-oxidanteffects, and for other purposes. Various methods of manufacture havebeen proposed Wlth the object of increasing the phosphorus and sulfurcontent of the hydrocarbon and establishing a phosphorus and sulfur bondof the desired type so as to enhance the lubricant properties to anextent permitting the use of smaller amounts of the compound forincorporation in the more or les inferior oils. The problem ofchemically binding desired proportions of phosphorus and sulfur to thesaturated hydrocarbons such as paraflinic and naphthenic materials, hasbeen particularly difiicult to solve.

It is an object of the present invention to provide an agent which initself is useful as a lubricant, and which will inhibit in markeddegree, acid and sludge formation, oxidation, and other common types oflubricant deterioration occurring under operating conditions.

A further object is to provide a lubricating oil containing this agentas an additive,

A further object is to provide an addition agent for lubricantscontaining a high percentage of phosphorus and. sulfur, and havingsuperior antioxidant qualities.

A further object is to provide an improved method of manufacture oflubricants and lubricant additives, providing a compound superior in theabove respects.

A further object is to provide as a lubricant or lubricant additive asaturated hydrocarbon material having a higher percentage content ofphosphorus and sulfur than a product obtained by the usual method.

Still a further object is to provide an improved method of manufactureof phosphorus-sulfur lubricants and lubricant additives, employingrelatively saturated hydrocarbons as the base material.

Other objects and advantages will be apparent from the followingdetailed description of the invention.

In accordance with the present invention, hydrocarbons are treated witha phosphorus sulfide in the presence of a catalytic agent from theactive metal and metalloid halide group. The

reaction products of the invention are characterized by high solubilityin lubricating oils and greases and are particularly valuable asadditives for lubricants such as the so-called extreme pressurelubricants, and also as additives for lubricating oils to improve thecorrosion, lacquer, sludge, viscosity increase, and other likecharacteristics of the lubricant. In addition, the metal derivativesformed from these products have these desired properties, and areespecially suitable when a lubricant having increased detergency isdesired.

It has been found that the base material employed in carrying out theinvention may comprise a hydrocarbon from any source. In its broadestapplication, the advantages of the invention result from the treatmentof the preferred hydrocarbon base material with a phosphorus sulfide, inthe presence of the active halide catalyst.

The invention is applicable broadly to the treatment of hydrocarbon oilssuch as mineral oils or mixtures thereof, and for more ready commercialapplication, is useful in the treatment of, for example, petroleumdistillates and lubricating residuums, oils produced by variouspolymerization methods, acid treated oils and solvent extracted oils.Oils modified by sulfurizing or chlorination may be employed as the basematerial, or as the lubricant body for incorporation of the product ofthe invention as an additive.

The invention has particular utility however in the treatment of themore saturated hydrocarbons which under ordinary conditions of reactioncombine with phosphorus sulfides in much less degree than the relativelyunsaturated hydrocarbons. Thus, for example, excellent results areobtained employing parafiinic or naphthenic hydrocarbons or mixturesthereof, ranging in carbon atom content from 10 to 40 carbon atoms, anexample of which is a so-called solvent extracted oil. Saturatedhydrocarbon base materials are found to possess inherently desirablelubricant properties which are further improved by the incorporationtherein of a phosphorus-sulfur constituent.

Of the phosphorus sulfides used as the reactant, phosphorus pentasulfideis preferred, because it is more readily available commercially and iseconomical. For this reason, phosphorus pentasulfide is employed in theillustrative examples of the invention to follow.

The quantity of phosphorus pentasulflde employed in carrying out thereaction may be in the order of from a fraction of one percent to abouttwenty percent by weight based upon the weight of the base hydrocarbonmaterial em- I ployed. The upper limit is dictated by economicconsiderations, the nature of the hydrocarbon employed and theproperties desired in the final product, and is not indicative of thescope of the invention in a limiting sense.

The reaction of the hydrocarbon base material and phosphoruspentasulfide constituent is carried out in the presence of an activehalide catalyst. Halides of elements including nonmetals such as boron,and metals such as aluminum, are particularly effective, and these arepreferred. Other halide catalysts are effective in more or less degree,and may include, for example, FeCla, ZIlC12, SnCh and other halidecompounds. The halide catalysts are well known and well defined as agroup and the art recognizes the scope of this definition. They aresometimes also referred to as a Friedel-Crafts catalyst because they areoften used in catalyzing that reaction.

The quantity of the halide agent employed preferably may range from0.05% Amounts in excess of 10% may be employed but achieve littlepractical result in terms of V improvement of the reaction compared tothe additional cost, and in some instances may undesirably modify thefinal oil product.

The halide catalyst employed in the reaction has the effect ofincreasing the percentage of phosphorus and sulfur incorporated in thehydrocarbon, over that obtained by carrying out the reaction in theabsence of the catalyst, particularly when a saturated hydrocarbon basematerial is employed. The halide catalyst has. the added desirableeffect of coagulating sludge and other residual solids formed during thereaction, thus facilitating filtration of the reaction product andincreasing the product yield.

The reaction is carried out at an elevated tern perature ranging between250 F. and 600 F., the preferred temperature being about 375 to 425 F.

The reaction may be carried out at atmospheric pressure. However,elevated pressures may be employed. The reaction may be completed in thepresence of air, or in an atmosphere of inert gas such as nitrogen.

The time of reaction may fall within an extended range, being a functionof temperature,

the amount of components to be reacted, mixing of the components duringthe reaction, etc. Employing atmospheric pressures and a reactiontemperature within the prescribed range, it has been found that areaction time of approximately one hour is ample to carry the reactionto completion, although it may extend to as much as six hours under somecircumstances.

When the reaction is complete, the liquid reaction product is treated toremove sludge components which may have formed, by settling,centrifuging or mechanical filtering.

Where it is desired that the lubricant or lubricant additives of theinvention have pronounced qualities of detergency, they may be convertedto their metal derivatives by methods well known to the art. Forexample, the compound may be reacted with one or more metal yieldingcompounds in the form of sulfides, oxides or hydroxides, which mayfurther comprise an alkali metal, or an alkaline earth compound such asbarium, calcium and strontium, or higher metals. These or other metalsshould be selected with reference to the proposed use of the additivecompound and the properties of detergency and/or oiliness desired in it.The heavier metals have excellent surface corrosion inhibitioncharacteristics.

The reaction of the additive compound to produce the metal derivativethereof may be in to 10.0%.- L

accordance with known practice, wherein an amount of a reactable metalcompound is added sufficient either to partially or completely reactwith the additive compound, as desired. Also ammonia or amines or othernitrogenous base may be used as well as carbides and cyanamides.Alcohols can be used to form the corresponding esters. These are allcompounds which combine with or replace acid hydrogen.

The mixture preferably is reacted at a temperature ranging between 200F. and 400 F., with stirring, one to a few hours. The presence of waterdesirably accelerates the reaction. The reaction product is settled andfiltered to re- 1 move any residual solids, and any water contentremaining may be removed by any usual method. The metal or otherderivatives may be employed by themselves as additives for a lubricatingoil, or a small amount added to the P2S5-S01Vellt extracted oiladditive, and are particularly useful in either case as detergents.

In some instances, it may be desirable to increase further the sulfurcontent of the additive compound. This may be accomplished by theinclusion of elemental sulfur or a material yielding elemental sulfurunder the reaction conditions present in the reaction mixture. Referenceto a reaction with the sulfide is not to exclude also a reaction withsulfur. The amount of sulfur employed depends on the degree ofsulfurization desired in the final additive product. An excellent highsulfur constituent additive is derived by employing 25 to 75% sulfur byweight of the phosphorus pentasulfide. The sulfur preferably is added tothe reaction mixture, carrying out the sulfurizing reactionsimultaneously with the reaction with the sulfide in the presence or thehalide catalyst. However, the additive compound may be sulfurizedfurther with elemental sulfur as a step subsequent to the phosphorussulfide-hydrocarbon reaction in the presence or absence of the catalyst.

The improved lubricant or lubricant additive compounds of the inventionare characterized by markedly higher anti-oxidant qualities than ahydrocarbon-phosphorus sulfide compound formed of the same base materialbut in the absence of the halide catalysts.

The amount of the additive to be mixed with an oil, grease or otherlubricant will depend upon factors of expense, the intended use of thelubricant, and the characteristics of the oil or grease. Oils having amarked tendency to oxidize or corrode metals require larger amounts ofthe additive. In general, for a lubricating oil, an effectiveconcentration range may comprise between 1% and 10% by weight, thepreferred concentration being approximately 2%. With some oils, theadditive in amounts as low as a fraction of a percent shows markedimprovement. The extreme upper range is dictated by economicconsiderations, and since the reaction product is itself a lubricantthere is no inoperative upper limit.

The invention may be further illustrated by the following examples andtables of tests of lubricants containing the new composition of theinvention, pointing out some of the advantages thereof. It is to beunderstood that these examples are intended only as practicalillustrations fully disclosing the practice of the invention, and arenot to be construed as limiting the scope thereof as defined in theclaims.

EXAMPLE I A typical component reaction charge may comprise 270 grams ofsolvent extracted oil, 30 grams of P285 and 3 grams of anhydrous A1013as the halide catalyst. The ingredients are mixed and heated to 500 F.and maintained at this temperature for one hour, with agitation. Thereaction mass is then filtered to remove sludge constituents. The liquidproduct analyzed 3.40% sulfur and 1.90% phosphorus.

EXAMPLE II 270 grams of solvent extracted oil is mixed with 30 grams ofP285 and the mixture saturated with BFa at room temperature. The mixtureis charged to a stirred bomb and reacted therein for one hour at 500 F.The reaction mass is then filtered. The liquid product analyzed 4.15%sulfur and 2.24% phosphorus.

To illustrate comparatively the value of the products of the inventionas additives for lubricants, a lubricating oil consisting of a solventextracted oil was combined with a number of additives representative ofthe invention, and the oil tested according to laboratory testprocedures for evaluating the service stability of oils, as published inIndustrial and Engineering Chemistry, Analytical Edition, vol. 17, No.5, May 1945, pages 302-309.

Essentially the laboratory test equipment consists of a vertical,thermostatically heated, large glass test tube, into which is placed apiece of steel tubing of about one-third its length and of much smallerdiameter. A piece of copperlead bearing strip is suspended within andfrom the upper end of the steel tube by a copper pin, and an air inletis provided for admitting air into the lower end of the steel tube insuch a way that in rising the air will cause the oil present tocirculate. The test tube is filled with an amount of the oil to betested which is at least sufficient to submerge the metals.

The ratios of surface active metals to the volume of oil in an internalcombustion test engine are nearly quantitatively duplicated in the testequipment. In the Standard test the temperature used is approximatelythe average temperature of the crankcase. The rate of air flow pervolume of oil is adjusted to the same as the average for a test enginein operation. Of the catalytic effects those due to iron are the mostimportant. ,They are empirically duplicated by the addition of a solubleiron salt. Those due to lead bromide are duplicated by its addition. Inthe Standard test, 0.012% of iron salt is added; and in the IronTolerance test this is increased to 0.05%. The duration of the test isadjusted to that usually used in engine type tests. As is shown by thedata in the papers referred to, the laboratory tests have beencorrelated with engine tests and the properties of the oil in an enginemay be determined from the result of the laboratory tests.

The results given in the following tables were obtained from testsusing:

A 160 cubic centimeter sample of the lubricant composition '70 liters ofair per hour 100 square centimeters of steel surface 4.4 squarecentimeters of copper-lead surface 1.0 square centimeter of coppersurface 0.10% by weight of lead bromide powder 0.05% soluble ironcalculated as FezOa (ferric 2-ethyl hexoate in C. P. benzene) ing thesetests.

The Iron Tolerance" tests are run at 280 F. for 36 hours. The used oilwas sufficient to enable the determination of all of the usual oiltests, viz. isopentane insolubles, viscosity, acid number, etc.

The data in the following tables show the results obtained in testingthe new lubricant additives by the tests described.

Tests on a solvent extracted oil base stock, and a lubricatingcomposition containing this oil and a number of additives were run underthe Iron Tolerance test conditions. For purposes of comparison, and toindicate more fully the advantages of the invention, tests wereperformed on a Pass-hydrocarbon product formed. in the absence of ahalide catalyst (column 2), on a reaction product of a halide catalyston a solvent extracted oil in the absence of P235 (column 5), and and ona sample of solvent extracted oil (column 1).

The following results are fully illustrative:

Table [Solvent extracted oil-60 min. reaction at 500 F., 10% P285 byweight.]

( P285 (3) P285 4 P235 (5) No P255 Description ig A1013 BFa 1% A1013 OilSEO SEO SEO SEO SEO Additive from Example No. #1 #2 Cone. of Additive byWeight. 0% Sludge-Pentane I n s 01 u b l e s (Mgms) 206. 4 52. 7 18.9 8.5 54.05 Acid Number. l4. 5 5. 0 2.6 3.0 10. 2 Viscosity In crease (S US)1095 467 342 1155 These data show the unusual improvement imparted tolubricants in every previously indicated characteristic, by thelubricant additives of the invention. It is to be noted that a solventextracted oil base comprising essentially saturated hydrocarbonmaterials was employed in conduct- This oil is an inherently bettergrade of oil in many respects and heretofore has been relativelydifiicult to combine with phosphorus and sulfur. The advantages of theproducts of the invention are even more fully realized when the productsare employed with ordinary base stock lubricants, having substantialamounts of more reactive hydrocarbon constituents, or the base materialemployed in carrying out the invention comprises a relatively morereactive hydrocarbon.

The marked improvement of the products of the invention prepared in thepresence of halide catalysts, over phosphorus pentasulflde-hydrocarbonreaction products prepared in accordance with. the usual methods in theabsence of a halide catalyst, specifically with regard to type of sludgeformation, acid number, and viscosity increase, is clearly indicated bythese tests.

The neutral or partially neutralized derivatives of the products of theinvention are particularly useful where increased oiliness and/ordetergency is desired in the lubricant product. It will be obvious toone skilled in the art that the products of the invention may beemployed as lubricants or as component parts of lubricants in ac-.-cordance with the invention, as set forth in the following claims.

The expression consisting essentially of as used herein is intended torefer to the components which are essentialto the composition,

'namely' the mineral lubricating oil'and .thea'ddi tive in accordancewith the invention, and the expression does not exclude other componentsfrom the composition which do not render it onsuitable for lubricantpurposes.

We claim:

1. The reaction product oi a saturated hydrocarbon oil and an amountwithin the. range of about one to about twenty percent by weight of aphosphorus sulfide reacted in the presence of not over 10% or" a halidecatalyst at a temperature injthe range of about 250 to about 600 so asto produce a lubricant.

2. The metal derivative of the reaction product set forth in claim 1selectedfrom' :the group consisting ofallrali metal and alkaline earthmetal derivatives.

3. A lubricant consisting essentially of a mineral lubricating oil andthe reaction product of a saturated hydrocarbon oil and an amount withinthe range of about one to about twenty percent by weight of a phosphorussulfide reacted in the presence of not over 10% of a halide catalyst ata temperature in the range of about 250 to about 600 F. so as to producea lubricant and containing reacted elemental sulfur.

l. A lubricant'consisting essentially of a mineral lubricating oil andthe metal derivative selected from the group consisting of alkali metaland alkaline earth metal derivatives of the reaction product of asaturated hydrocarbon oil and anamo'unt within the range of about one toabout twenty percent by weight of phosphorus pentasulfide reacted in thepresence of not over 10% of. a halide catalyst at a temperature therange of about 250 to about 600 P. so as to produce a lubricant.

5. A lubricant consisting essentially of a mineral lubricating oil andthe reaction product of a saturated hydrocarbon oil and an amount withinthe range of about one to about twenty per? cent by weight of aphosphorus sulfide reacted in the presence of not over 10% of a halidecatalyst at a temperature in the range of about 250" to about 600 F. soas to produce a lubricant.

6. A lubricant consisting essentially of a mineral lubricating oil andthe reaction product of a saturated hydrocarbon-oil and an amount withinthe range of about one to about twenty percent by weight of phosphoruspentasulfide reacted in the presence of not over 10% of a halideCatalyst at a temperature in the range or" about 250 to about 600 F. soas to produce a lubricant.

7. A lubricant consisting essentially of a mineral. lubricating oil andthe reaction product of a solvent extracted oil and an amountwithin therange of about one to about twenty percent by weight of phosphoruspentasulfide reacted in the presence of not over 10% of a halidecatalyst at a temperature in the range of about 250 to about 600 '5. soas to produce a lubricant.

8. A lubricant consisting essentially of a mineral lubricating oil andthe metal derivative selected from the group consisting of alkali metaland alkaline earth metal derivatives of the reaction product of asolvent extracted oil and an amount within the range of about one toabout twenty percent by weight of phosphorus pentasulfide reacted in thepres nce of not over 10% of a halide catalyst at a temperature in therange or" about 250 to about 600 so as to produce a lubricant.

9. As a lubricant additive the reaction product of a saturatedhydrocarbon oil and; an amount within the range of about one to abouttwenty percent by weight'of a phosphorus sulfide in the presence of notover 10% of aluminumchloride at a temperature in the range of about 250to about 600 F. so as to produce an additivefor improving a minerallubricating oil.

10. As a lubricant additive the reaction product of a'saturatedhydrocarbon oil and an amount within the range of about one to about,twenty percent by weight of a phosphorus sulfide in the presence of notover 10% of boron trifiuorideat a temperature in the range of about 250to about 600 F. so as to produce an additive for improving a minerallubricatin oil.

11. A lubricating composition consisting essentially of a major portionof a lubricating oil and an amount to inhibit the oxidativedeterioration of the oil of the reaction product of a saturatedhydrocarbon oil and an amount within the range of about one to abouttwenty percent by weight of a phosphorus sulfide reacted in the presenceof not over 1.0% of a halide catalyst at a tempera. ture in the range ofabout 250 to about 600 F. so as to produce an additive for improving amineral lubricatin oil.

12. A lubricating composition consisting essen tially of a major portionof a lubricating oil, and an amount to inhibit the oxidativedeterioration of the oil of the reaction product of a saturatedhydrocarbon oil and an amount within the range of about one to abouttwenty percent by weight of phosphorus pentasulfide reacted in thepresence of not over 10% of a halide catalyst at a temperature in therange of about 250 to about 000 F. so as to produce an additive forimproving a mineral lubricating oil.

13. A method of producing a. lubricant additive comprising reactin asaturated hydrocarbon oil with. an amount within the range of about oneto about twenty percent by weight of a phos phorus sulfide in thepresence of not over 10% of a halide catalyst at a temperature in therange of about 250 to about 600 F. so as to produce a lubricant.

14. A method of producing alubricant additive comp-rising reacting asaturated hydr carbon o'il with'an amount within the range of about oneto about twenty percent by weight of phosphorus pentasulfide in thepresence of not over 10% or a halide catalytic agent at a temperature inthe range of about 250 to about 600 F. so as to produce a lubricant.

15. A method of producing a compound for use as an additive with alubricating oil comprising reacting a saturated hydrocarbon oil with anamount within therange of about one to about twenty percent by weight ofa phosphorus sulfide in the presence of not over 10% or" a halide catalyst at a temperature in the range of about 250 toabout 600 P. so astoproduce an additive for improving a mineral lubricatin oil, andseparating the reaction product from residues formed during thereaction. V

16. A method of producing a compound suit able for use as an additivewith a lubricating oil comprising reacting a solvent extracted oil basewith an amount within the range of about one to about twenty percent byweight of phosphorus pentasulfide in the presence of not over 10% of ahalide catalyst at a temperature in the range of about 250 to about 600F. so as to produce an additive-for improving a mineral lubricating oiland separating the reaction product from the residues formed during thereaction.

17. A method of producing a lubricantadditive comprising reacting asaturated hydro'carbon ioil with an amount within the range of about oneto about twenty percent by weight of a phosphorus sulfide and elementalsulfur in the presence of not over 10% of a halide catalyst at atemperature in the range of about 250 to about 600 F. so as to produce alubricant.

18. A method of producing a lubricant additive comprising reacting asaturated hydrocarbon oil With an amount Within the range of about oneto about twenty percent by weight of phos phorus sulfide in the presenceof notover 10% of a halide catalyst at a temperature in the range ofabout 250 to about 600 F. so as to produce a lubricant, and reacting atleast part of the reaction product with a metal selected from the groupconsisting of alkali metals and alkaline earth metals.

19. The metal derivative selected from the group consisting of alkaliand alkaline earth metal derivatives of the reaction product of asaturated hydrocarbon oil and an amount within REFERENCES CITED Thefollowing references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,176,884 Butz et a1 Oct. 24,1939 2,316,087 Gaynor et a1 Apr. 6, 1943 2,367,468 Mixon et a1 Jan. 16,1945 2,398,429 Hughes Apr. 16, 1946 2,449,934 Giammaria Sept. 21, 19482,456,336 Smith et a1. Dec. 14, 1948 2,476,812 Buckmann et a1. July 19,1949

1. THE REACTION PRODUCT OF A SATURATED HYDROCARBON OIL AND AN AMOUNTWITHIN THE RANGE OF ABOUT ONE TO ABOUT TWENTY PERCENT BY WEIGHT OF APHOSPHORUS SULFIDE REACTED IN THE PRESENCE OF NOT OVER 10% OF A HALIDECATALYST AT A TEMPERATURE IN THE RANGE OF ABOUT 250* TO ABOUT 600* F. SOAS TO PRODUCE A LUBRICANT.